Use of a second-order reliability method to estimate the failure probability of an integrated energy system

A shortage of gas supply renders gas expensive and may even cause power outages. Estimation of the failure probability of gas supply is an essential component of an integrated energy system. To ensure that failure probability estimation is relevant to an actual project, energy network constraints should be fully considered in calculations. Here, this paper develops a second-order reliability estimation method to cope with the nonlinearity caused by network constraints. Under conditions of integrated energy supply, correlations exist between the extremes of wind power, the heat loads, and failure of the natural gas supply. This paper illustrates the proposed method by comparing the results to those of other methods. The proposed method is efficient in terms of both accuracy and computational time. Compared to a mixed algorithm, which required 1101.1 s to simulate tens of thousands of samples, the proposed method takes 3.5 s to obtain a failure probability. Also, the proposed method improves accuracy by at least 10-fold compared to that of a first-order reliability method.